openfs.c revision 25567a7b0fa98b390fd1ff0d4702b29c23a75bbb
1/* 2 * openfs.c --- open an ext2 filesystem 3 * 4 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o. 5 * 6 * %Begin-Header% 7 * This file may be redistributed under the terms of the GNU Library 8 * General Public License, version 2. 9 * %End-Header% 10 */ 11 12#include <stdio.h> 13#include <string.h> 14#if HAVE_UNISTD_H 15#include <unistd.h> 16#endif 17#include <fcntl.h> 18#include <time.h> 19#if HAVE_SYS_STAT_H 20#include <sys/stat.h> 21#endif 22#if HAVE_SYS_TYPES_H 23#include <sys/types.h> 24#endif 25 26#include "ext2_fs.h" 27 28 29#include "ext2fs.h" 30#include "e2image.h" 31 32blk64_t ext2fs_descriptor_block_loc2(ext2_filsys fs, blk64_t group_block, 33 dgrp_t i) 34{ 35 int bg; 36 int has_super = 0; 37 blk64_t ret_blk; 38 39 if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) || 40 (i < fs->super->s_first_meta_bg)) 41 return (group_block + i + 1); 42 43 bg = EXT2_DESC_PER_BLOCK(fs->super) * i; 44 if (ext2fs_bg_has_super(fs, bg)) 45 has_super = 1; 46 ret_blk = ext2fs_group_first_block2(fs, bg) + has_super; 47 /* 48 * If group_block is not the normal value, we're trying to use 49 * the backup group descriptors and superblock --- so use the 50 * alternate location of the second block group in the 51 * metablock group. Ideally we should be testing each bg 52 * descriptor block individually for correctness, but we don't 53 * have the infrastructure in place to do that. 54 */ 55 if (group_block != fs->super->s_first_data_block && 56 ((ret_blk + fs->super->s_blocks_per_group) < 57 ext2fs_blocks_count(fs->super))) 58 ret_blk += fs->super->s_blocks_per_group; 59 return ret_blk; 60} 61 62blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i) 63{ 64 return ext2fs_descriptor_block_loc2(fs, group_block, i); 65} 66 67errcode_t ext2fs_open(const char *name, int flags, int superblock, 68 unsigned int block_size, io_manager manager, 69 ext2_filsys *ret_fs) 70{ 71 return ext2fs_open2(name, 0, flags, superblock, block_size, 72 manager, ret_fs); 73} 74 75/* 76 * Note: if superblock is non-zero, block-size must also be non-zero. 77 * Superblock and block_size can be zero to use the default size. 78 * 79 * Valid flags for ext2fs_open() 80 * 81 * EXT2_FLAG_RW - Open the filesystem for read/write. 82 * EXT2_FLAG_FORCE - Open the filesystem even if some of the 83 * features aren't supported. 84 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device 85 */ 86errcode_t ext2fs_open2(const char *name, const char *io_options, 87 int flags, int superblock, 88 unsigned int block_size, io_manager manager, 89 ext2_filsys *ret_fs) 90{ 91 ext2_filsys fs; 92 errcode_t retval; 93 unsigned long i, first_meta_bg; 94 __u32 features; 95 int groups_per_block, blocks_per_group, io_flags; 96 blk64_t group_block, blk; 97 char *dest, *cp; 98#ifdef WORDS_BIGENDIAN 99 struct ext2_group_desc *gdp; 100 int j; 101#endif 102 103 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER); 104 105 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); 106 if (retval) 107 return retval; 108 109 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 110 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 111 fs->flags = flags; 112 /* don't overwrite sb backups unless flag is explicitly cleared */ 113 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY; 114 fs->umask = 022; 115 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 116 if (retval) 117 goto cleanup; 118 strcpy(fs->device_name, name); 119 cp = strchr(fs->device_name, '?'); 120 if (!io_options && cp) { 121 *cp++ = 0; 122 io_options = cp; 123 } 124 125 io_flags = 0; 126 if (flags & EXT2_FLAG_RW) 127 io_flags |= IO_FLAG_RW; 128 if (flags & EXT2_FLAG_EXCLUSIVE) 129 io_flags |= IO_FLAG_EXCLUSIVE; 130 if (flags & EXT2_FLAG_DIRECT_IO) 131 io_flags |= IO_FLAG_DIRECT_IO; 132 retval = manager->open(fs->device_name, io_flags, &fs->io); 133 if (retval) 134 goto cleanup; 135 if (io_options && 136 (retval = io_channel_set_options(fs->io, io_options))) 137 goto cleanup; 138 fs->image_io = fs->io; 139 fs->io->app_data = fs; 140 retval = ext2fs_get_memalign(SUPERBLOCK_SIZE, 512, &fs->super); 141 if (retval) 142 goto cleanup; 143 if (flags & EXT2_FLAG_IMAGE_FILE) { 144 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr), 145 &fs->image_header); 146 if (retval) 147 goto cleanup; 148 retval = io_channel_read_blk(fs->io, 0, 149 -(int)sizeof(struct ext2_image_hdr), 150 fs->image_header); 151 if (retval) 152 goto cleanup; 153 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE) 154 return EXT2_ET_MAGIC_E2IMAGE; 155 superblock = 1; 156 block_size = fs->image_header->fs_blocksize; 157 } 158 159 /* 160 * If the user specifies a specific block # for the 161 * superblock, then he/she must also specify the block size! 162 * Otherwise, read the master superblock located at offset 163 * SUPERBLOCK_OFFSET from the start of the partition. 164 * 165 * Note: we only save a backup copy of the superblock if we 166 * are reading the superblock from the primary superblock location. 167 */ 168 if (superblock) { 169 if (!block_size) { 170 retval = EXT2_ET_INVALID_ARGUMENT; 171 goto cleanup; 172 } 173 io_channel_set_blksize(fs->io, block_size); 174 group_block = superblock; 175 fs->orig_super = 0; 176 } else { 177 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET); 178 superblock = 1; 179 group_block = 0; 180 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super); 181 if (retval) 182 goto cleanup; 183 } 184 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE, 185 fs->super); 186 if (retval) 187 goto cleanup; 188 if (fs->orig_super) 189 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE); 190 191#ifdef WORDS_BIGENDIAN 192 fs->flags |= EXT2_FLAG_SWAP_BYTES; 193 ext2fs_swap_super(fs->super); 194#else 195 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 196 retval = EXT2_ET_UNIMPLEMENTED; 197 goto cleanup; 198 } 199#endif 200 201 if (fs->super->s_magic != EXT2_SUPER_MAGIC) { 202 retval = EXT2_ET_BAD_MAGIC; 203 goto cleanup; 204 } 205 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) { 206 retval = EXT2_ET_REV_TOO_HIGH; 207 goto cleanup; 208 } 209 210 /* 211 * Check for feature set incompatibility 212 */ 213 if (!(flags & EXT2_FLAG_FORCE)) { 214 features = fs->super->s_feature_incompat; 215#ifdef EXT2_LIB_SOFTSUPP_INCOMPAT 216 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 217 features &= !EXT2_LIB_SOFTSUPP_INCOMPAT; 218#endif 219 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { 220 retval = EXT2_ET_UNSUPP_FEATURE; 221 goto cleanup; 222 } 223 224 features = fs->super->s_feature_ro_compat; 225#ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT 226 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES) 227 features &= !EXT2_LIB_SOFTSUPP_RO_COMPAT; 228#endif 229 if ((flags & EXT2_FLAG_RW) && 230 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) { 231 retval = EXT2_ET_RO_UNSUPP_FEATURE; 232 goto cleanup; 233 } 234 235 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) && 236 (fs->super->s_feature_incompat & 237 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) { 238 retval = EXT2_ET_UNSUPP_FEATURE; 239 goto cleanup; 240 } 241 } 242 243 if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) > 244 EXT2_MAX_BLOCK_LOG_SIZE) { 245 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 246 goto cleanup; 247 } 248 if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 249 EXT4_FEATURE_RO_COMPAT_BIGALLOC) && 250 (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) { 251 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 252 goto cleanup; 253 } 254 fs->blocksize = EXT2_BLOCK_SIZE(fs->super); 255 if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) { 256 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 257 goto cleanup; 258 } 259 fs->cluster_ratio_bits = fs->super->s_log_cluster_size - 260 fs->super->s_log_block_size; 261 if (EXT2_BLOCKS_PER_GROUP(fs->super) != 262 EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) { 263 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 264 goto cleanup; 265 } 266 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) * 267 EXT2_INODE_SIZE(fs->super) + 268 EXT2_BLOCK_SIZE(fs->super) - 1) / 269 EXT2_BLOCK_SIZE(fs->super)); 270 if (block_size) { 271 if (block_size != fs->blocksize) { 272 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE; 273 goto cleanup; 274 } 275 } 276 /* 277 * Set the blocksize to the filesystem's blocksize. 278 */ 279 io_channel_set_blksize(fs->io, fs->blocksize); 280 281 /* 282 * If this is an external journal device, don't try to read 283 * the group descriptors, because they're not there. 284 */ 285 if (fs->super->s_feature_incompat & 286 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 287 fs->group_desc_count = 0; 288 *ret_fs = fs; 289 return 0; 290 } 291 292 if (EXT2_INODES_PER_GROUP(fs->super) == 0) { 293 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 294 goto cleanup; 295 } 296 297 /* 298 * Read group descriptors 299 */ 300 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super); 301 if (blocks_per_group == 0 || 302 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) || 303 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) || 304 EXT2_DESC_PER_BLOCK(fs->super) == 0 || 305 fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) { 306 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 307 goto cleanup; 308 } 309 fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) - 310 fs->super->s_first_data_block, 311 blocks_per_group); 312 if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) != 313 fs->super->s_inodes_count) { 314 retval = EXT2_ET_CORRUPT_SUPERBLOCK; 315 goto cleanup; 316 } 317 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count, 318 EXT2_DESC_PER_BLOCK(fs->super)); 319 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize, 320 &fs->group_desc); 321 if (retval) 322 goto cleanup; 323 if (!group_block) 324 group_block = fs->super->s_first_data_block; 325 if (group_block == 0 && fs->blocksize == 1024) 326 group_block = 1; /* Deal with 1024 blocksize && bigalloc */ 327 dest = (char *) fs->group_desc; 328 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super); 329 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) 330 first_meta_bg = fs->super->s_first_meta_bg; 331 else 332 first_meta_bg = fs->desc_blocks; 333 if (first_meta_bg) { 334 retval = io_channel_read_blk(fs->io, group_block+1, 335 first_meta_bg, dest); 336 if (retval) 337 goto cleanup; 338#ifdef WORDS_BIGENDIAN 339 gdp = (struct ext2_group_desc *) dest; 340 for (j=0; j < groups_per_block*first_meta_bg; j++) { 341 gdp = ext2fs_group_desc(fs, fs->group_desc, j); 342 ext2fs_swap_group_desc2(fs, gdp); 343 } 344#endif 345 dest += fs->blocksize*first_meta_bg; 346 } 347 for (i=first_meta_bg ; i < fs->desc_blocks; i++) { 348 blk = ext2fs_descriptor_block_loc2(fs, group_block, i); 349 retval = io_channel_read_blk64(fs->io, blk, 1, dest); 350 if (retval) 351 goto cleanup; 352#ifdef WORDS_BIGENDIAN 353 for (j=0; j < groups_per_block; j++) { 354 /* The below happens to work... be careful. */ 355 gdp = ext2fs_group_desc(fs, fs->group_desc, j); 356 ext2fs_swap_group_desc2(fs, gdp); 357 } 358#endif 359 dest += fs->blocksize; 360 } 361 362 fs->stride = fs->super->s_raid_stride; 363 364 /* 365 * If recovery is from backup superblock, Clear _UNININT flags & 366 * reset bg_itable_unused to zero 367 */ 368 if (superblock > 1 && EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 369 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) { 370 dgrp_t group; 371 372 for (group = 0; group < fs->group_desc_count; group++) { 373 ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT); 374 ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT); 375 ext2fs_bg_itable_unused_set(fs, group, 0); 376 } 377 ext2fs_mark_super_dirty(fs); 378 } 379 380 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR; 381 *ret_fs = fs; 382 return 0; 383cleanup: 384 if (flags & EXT2_FLAG_NOFREE_ON_ERROR) 385 *ret_fs = fs; 386 else 387 ext2fs_free(fs); 388 return retval; 389} 390 391/* 392 * Set/get the filesystem data I/O channel. 393 * 394 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true. 395 */ 396errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io) 397{ 398 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 399 return EXT2_ET_NOT_IMAGE_FILE; 400 if (old_io) { 401 *old_io = (fs->image_io == fs->io) ? 0 : fs->io; 402 } 403 return 0; 404} 405 406errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io) 407{ 408 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 409 return EXT2_ET_NOT_IMAGE_FILE; 410 fs->io = new_io ? new_io : fs->image_io; 411 return 0; 412} 413 414errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io) 415{ 416 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0) 417 return EXT2_ET_NOT_IMAGE_FILE; 418 fs->io = fs->image_io = new_io; 419 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW | 420 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY; 421 fs->flags &= ~EXT2_FLAG_IMAGE_FILE; 422 return 0; 423} 424